<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <script src="https://unpkg.com/vue@3/dist/vue.global.js"></script>
</head>
<body>
    <div id="app">
        {{p1}}
        </div>
        <script>
            const app = Vue.createApp({
                date(){
                    return{
                        p1:10
                    }
                },
                beforeCreate(){
                    console.log(this.p1);
                },
                created(){
                    console.log(this.p1);
                    
                },
                beforeMount(){
                    this.p1 = 20;
                },
                mounted(){
                    this.p1 = 30;
                }
            })
            app.mount('#app')
    </script>
</body>
</html>